418 SPECIAL HISTOLOGY. 



distribution and termination, so far as is known, presents nothing 

 peculiar. 



Terminal loops within the trunks of nerves had been already noticed 

 by Gerber, and have lately been described by Valentin in the vagus 

 (pectoral portion) of the Mouse and Shrew-mouse, but without their 

 expressing any opinion with respect to their signification. Still more 

 mysterious are the nervous filaments seen by Remak and Bochdalek, 

 coming out from, and again re-entering the brain. 



123. Granglionic Nerves. Under this name, perhaps, is most 

 suitably designated the n. sympathicus, as it is termed, the sympa- 

 thetic or vegetative nervous system, as it presupposes no physiological 

 hypothesis, but simply expresses the fact, which, anatomically, is most 

 apparent to the eye. The ganglionic nerves are neither a wholly inde- 

 pendent part of the nervous system (Reil, Bichat), nor a mere section of 

 the cerebro-spinal nerves ; but on the one hand, from the very numerous 

 fine nerve-fibres originating in their ganglia ganglion-fibres of the sym- 

 pathetic, form an independent system ; whilst on the other, they are 

 also connected with the spinal cord and brain, owing to their receiving a 

 smaller number of fibres of the other nerves. Upon comparing the 

 ganglionic nerves with the cerebro-spinal, we find, that the former, as 

 they are constituted from a double source, in a certain respect undoubt- 

 edly resemble the latter, which are also formed from ganglionic fibres of 

 the spinal ganglia, and from others proceeding from the cord ; but they 

 differ, particularly in this respect, that they possess a much greater 

 number of independent elements, of ganglia and ganglionic fibres, and 

 enter into much more numerous anastomoses with each other. Conse- 

 quently, although we appear to be justified from an anatomical point of 

 view, in considering the ganglionic nerves by themselves, still they must 

 not be regarded as something altogether peculiar, seeing that, essentially, 

 every nerve exhibits the same principal elements, and some cerebral 

 nerves, vagus, glossopharyngeus, possess even numerous peripheral 

 ganglia ; and moreover, because comparative Anatomy shows that they 

 are produced from the spinal nerves, and Physiology the absence of 

 peculiar functions in them. 



124. The principal trunk of the ganglionic nerves (nervus sympa- 

 thicus). The n. sympathicus in man appears as a whitish, or white 

 nerve, the dark-bordered fibres of which usually run parallel with each 

 other, without divisions or anastomoses, some measuring 0-0025-0-006 

 of a line or even more, and others not more than 0-0012-0-0025 of a 



